Printhead nozzle having heater of higher resistance than contacts

Abstract

A printhead nozzle is provided having a plurality of electrodes, a heater having contacts abutting the electrodes, a heater element for heating a quantity of fluid and sloped side portions extending between the heater element and the contacts, and a nozzle spaced from the heater such that the heated fluid is ejected through the nozzle. The heater element has higher electrical resistance than the contacts and the sloped side portions.

1. A printhead nozzle comprising:
 a plurality of electrodes; 
 a heater having contacts abutting the electrodes, a heater element for heating a quantity of fluid and sloped side portions extending between the heater element and the contacts; and 
 a nozzle spaced from the heater such that the heated fluid is ejected through the nozzle, 
 wherein the heater element has higher electrical resistance than the contacts and the sloped side portions. 
 
     
     
       2. A printhead nozzle according to  claim 1  wherein the heater comprises TiAlN. 
     
     
       3. A printhead nozzle according to  claim 1  wherein the heater element is ring shaped. 
     
     
       4. A printhead nozzle according to  claim 1  wherein the heater element is coated with a passivating material. 
     
     
       5. A printhead nozzle according to  claim 1  wherein the heater element is configured such that an actuation energy of less than 500 nanojoules is required to be applied to that heater element to heat that heater element sufficiently to cause the ejection of said drop. 
     
     
       6. A printhead nozzle according to  claim 1  incorporated in a structure that is formed by chemical vapor deposition. 
     
     
       7. A printhead nozzle according to  claim 6  wherein the structure is less than 10 microns thick. 
     
     
       8. A printhead nozzle according to  claim 1  wherein the heater element is formed of solid material more than 90% of which, by atomic proportion, is constituted by at least one periodic element having an atomic number below 50. 
     
     
       9. A printhead nozzle according to  claim 1  wherein the heater element is substantially covered by a conformal protective coating, the coating of having been applied substantially to all sides of the heater element simultaneously such that the coating is seamless.